The Moisture Content Effect on Some Physical and Mechanical Properties of Corn (Sc 704)

Physical and mechanical properties of grains are necessary for designing the facility of storage, handling andprocessing of agricultural products. Physical and mechanical properties of corn grains were determined as afunction of moisture content in the range of 4.73-22% w.b. (wet basis) using standard techniques. The averagegrainvolume, surface area and aspect ratio ranged from 11.62 to 12.60 mm, 7.27 to 7.98 mm, 4.47 to 4.71 mm, 7.20 to7.77 mm and 7.63 to 7.96 mm, 7.77 to 8.43 mm, 62.31% to 62.00%, 209.66 to 265.00 mm3, 137.69 to 160.09mm2 and 63.05% to 63.77% as the moisture content changed from 4.73-22% w.b. With increase in moisturecontent, the bulk density was found to decrease from 710 to 649 kgm-3 whereas true density and porosityincreased from 1250 to 1325 kgm-3 and 43.2% to 51.02%. In the moisture range from 4.73% to 22% w.b., studieson rewetted corn grains showed that the thousand grain weight (TGW) increased linearly from 271.0 to 321.4 g. The static coefficient of friction of corn grains increased linearly against surfaces of three materials, namely, plastic (0.32–0.51), plywood (0.48–0.60) and galvanized iron (0.38–0.65) and the static angle of reposeincreased from 49º to 58º when the moisture content increased from 4.73% to 22% w.b. The mechanicalproperties of corn were determined in terms of average rupture force and rupture energy. Rupture energy of corngrains generally increased in magnitude with an increase in moisture content, while rupture force decreased forcompression